Gina Gershon Recalls Almost Breaking Tom Cruise's Nose During Sex Scene

Gina Gershon knows all about playing rough in the sack ... with Tom Cruise, no less, and she's sharing an awkward tale about her first ever sex scene with her "Cocktail" costar.

The actress had mixed emotions as she recalled the intimate on-camera moment during her appearance Wednesday on "Watch What Happens Live," where she gleefully shared behind-the-scenes factoids from filming with Tom in the '80s.

As she put it ... TC was a great scene partner and totally took care of her during her first time faking sex on cam, except for one catastrophic moment. Gina warned Tom she was "very ticklish" and told him not to go there when they filmed the scene.

She added ... "In one take I have to say, I think he wanted a reaction, he grabbed my stomach and I kneed him right in the nose."

Understandably, Gina felt terrible about her literal knee-jerk reaction ... and she apologized profusely. But Gina said Tom was unbothered by the accidental nose job, and said he even took accountability for crossing a boundary.

Gina and Tom's on-screen chemistry did not trickle off-screen, however ... as the actress told host Andy Cohen, TC was very married at the time ... and his former wife, Mimi Rogers, was very present on the "Cocktail" set.

She quipped, "But we did kiss as much as we could. I think we should kiss more."